RBF Morph: mesh morphing in OpenFoam

RBF Morph: mesh morphing
in OpenFoam
Dr. Marco Evangelos Biancolini
University of Rome “Tor Vergata”
HPC enabling of OpenFOAM for CFD applications @ CINECA, 26-28 March 2014
Cineca - BOLOGNA
RBF Morph Training – PRACE
School 2013
Session #1
General Introduction of RBF Morph, Features with examples
http://videolectures.net/prace2013_biancolini_rbf_morph/
Session #2
Basic Usage of RBF Morph, Examples and Live demonstration
http://videolectures.net/prace2013_biancolini_rbf_morph_hands_on/
Session #3
Advanced Usage of RBF Morph, Multi-solve, Free surface
Deformation, STL target, Back to CAD, WB coupling
RBF Morph Training Material
Web Portal: www.rbf-morph.com frequently updated with News
Download Area: http://rbf-morph.com/index.php/download
•
animations, technical papers, conference presentations
•
for registered users (usr:ANSYS_COM, pwd:ANSYS_COM)
YouTube: www.youtube.com/user/RbfMorph video tutorials
Documentation Package (on box.com reserved area):
•
User Guide / Installation Notes
•
Tutorials (complete of support files folders)
Linkedin: https://www.linkedin.com/company/rbf-morph/
E-mail support: [email protected]
RBF Morph Training
General Introduction of RBF Morph, Features
with examples
Dr. Marco Evangelos Biancolini
Outline
•
•
•
•
RBF Morph tool presentation
Ongoing Researches
Industrial Applications
Hands On
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
RBF Morph tool presentation
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Morphing & Smoothing
• A mesh morpher is a tool capable to perform mesh
modifications, in order to achieve arbitrary shape changes and
related volume smoothing, without changing the mesh topology.
• In general a morphing operation can introduce a reduction of the
mesh quality
• A good morpher has to minimize this effect, and maximize the
possible shape modifications.
• If mesh quality is well preserved, then using the same mesh
structure it’s a clear benefit (remeshing introduces noise!).
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
RBF Morph software line
• Awarded mesh morphing software
available as an add-on for ANSYS Fluent
CFD solver
• HPC RBF general purposes library (state
of the art algorithms, parallel, GPU).
• Stand alone morphing software +
smoothing commands (OpenFoam,
Nastran, Step, STL, Elsa, CFD++)
• ANSYS Mechanical ACT module (first
release planned in June 2014)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
RBF Morph Features
• Add on fully integrated within Fluent (GUI, TUI &
solving stage) and Workbench
• Mesh-independent RBF fit used for surface
mesh morphing and volume mesh smoothing
• Parallel calculation allows to morph large size
models (many millions of cells) in a short time
• Management of every kind of mesh element type
(tetrahedral, hexahedral, polyhedral, etc.)
• Support of the CAD re-design of the morphed
surfaces
• Multi fit makes the Fluent case truly parametric
(only 1 mesh is stored)
• Precision: exact nodal movement and exact
feature preservation (RBF are better than FFD).
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Mesh Morphing with Radial Basis Functions
• A system of radial functions is used to fit a solution for
the mesh movement/morphing, from a list of source
points and their displacements.
• The RBF problem definition does not depend on the mesh
• Radial Basis Function interpolation is used to derive the
displacement in any location in the space, each
component of the displacement is interpolated:






N

x
x
x
x
x


v

s
x



x

x




x


y


z

x
x
i
k
1
2
3
4

i
i 1

N

y
y
y
y
y
v y  s y x     i  x  x ki  1   2 x   3 y   4 z
i 1

N
 v  s x    z  x  x   z   z x   z y   z z

z
i
ki
1
2
3
4
 z
i 1

HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
One pt at center 80 pts at border
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Effect on surface (gs-r)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Effect on surface (cp-c4)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Control of volume mesh (1166 pts)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Morphing the volume mesh
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Background: RBF Theory
• A system of radial functions is used to fit a solution for the
mesh movement/morphing, from a list of source points and their
displacements. This approach is valid for both surface shape
changes and volume mesh smoothing.
• The RBF problem definition does not depend on the mesh
• Radial Basis Function interpolation
is used to derive the displacement
in any location in the space, so it is
also available in every grid node.
• An interpolation function composed by a
radial basis and a polynomial is defined.
sx     i  x  xi   hx 
N
i 1
hx    1 x   3 y   4 z
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Background: RBF Theory
• A radial basis fit exists if desired
values are matched at source points
with a null poly contribution
• The fit problem is associated with the
solution of a linear system
• M is the interpolation matrix
• P is the constraint matrix
• g are the scalar values prescribed at
source points
•  and  are the fitting coefficients
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
   
0    qx 
s xki  g xki
1 i  N
N
i 1
M
 T
P
i
ki
P  γ   g 
    
0  β   0 

M ij   x ki  x k j
1 xk01

1 xk02
P
 
1 xk0
N

yk01
yk02

yk0N

1 i
z k01
zk02

zk0N
jN







www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Background: RBF Theory
• The radial function can be
fully or compactly supported.
The bi-harmonic kernel fully
supported gives the best
results for smoothing.
• For the smoothing problem
each component of the
displacement prescribed at
the
source
points
is
interpolated as a single scalar
field.
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
Radial Basis Function
 (r )
Spline type (Rn)
r , n odd
Thin plate spline (TPSn)
r log r , n even
n
n
Multiquadric(MQ)
1 r 2
1
Inverse multiquadric (IMQ)
1 r2
1
1 r2
2
e r
Inverse quadratic (IQ)
Gaussian (GS)






N



v

s
x

 ix x  x ki  1x   2x x   3x y   4x z

x
 x
i 1

N

y
y
y
y
y
v y  s y x     i  x  x ki  1   2 x   3 y   4 z
i 1

N
 v  s x    z  x  x   z   z x   z y   z z

z
i
ki
1
2
3
4
 z
i 1

www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Background: accelerating the solver
• The evaluation of RBF at a point has a cost of order N
• The fit has a cost of order N3 for a direct fit (full populated
matrix); this limit to ~10.000 the number of source points that
can be used in a practical problem
• Using an iterative solver (with a good pre-conditioner) the fit
has a cost of order N2; the number of points can be increased
up to ~70.000
• Using also space partitioning to accelerate fit and evaluation
the number of points can be increased up to ~300.000
• The method can be further accelerated using fast preconditioner building and FMM RBF evaluation…
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Background: solver performances escalation
• 10.000 RBF centers FIT
•
120 minutes Jan
2008
•
5 seconds Jan 2010
• Largest fit 2.600.000 133
minutes
• Largest model morphed
300.000.000 cells
• Fit and Morph a
100.000.000 cells model
using 500.000 RBF
centers within 15 minutes
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
#points
2010
(Minutes)
2008
(Minutes)
3.000
0 (1s)
15
10.000
0 (5s)
120
40.000
1 (44s)
Not
registered
160.000
4
Not
registered
650.000
22
Not
registered
2.600.000
133
Not
registered
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Coming soon: GPU acceleration!
• Single RBF complete
evaluation
• Unit random cube
• GPU: Kepler 20 2496
CUDA Cores
GPU Clock 0.71 GHz
• CPU: quad core
Intel(R) Xeon(R) CPU
E5-2609 0 @
2.40GHz
#points
CPU
GPU
speed up
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
100000
150000
200000
0,098402
0,319329
0,667639
1,135127
1,721781
2,451661
3,306897
4,286706
5,390029
6,707721
26,13633
58,96981
115,3628
0,004637
0,011746
0,024982
0,038352
0,054019
0,079459
0,108568
0,134978
0,181181
0,2135
0,745482
1,735367
2,861737
21,2
27,2
26,7
29,6
31,9
30,9
30,5
31,8
29,7
31,4
35,1
34,0
40,3
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Scaling plot
• Complexity is expected to
grow as N 2
• GPU observed as
N 1.87
• CPU observed as
N 2.174
• Estimation at one million
points:
GPU: 59 s
CPU: 2783 s
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
3
110
100
10
1
0.1
0.01
3
110
3
110
4
110
5
110
6
110
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
How it Works: the work-flow
• RBF Morph basically requires three different steps:
• Step 1 setup and definition of the problem (source points
and displacements).
• Step 2 fitting of the RBF system (write out .rbf + .sol).
• Step 3 [SERIAL or PARALLEL] morphing of the surface
and volume mesh (available also in the CFD solution
stage it requires only baseline mesh and .rbf + .sol files).
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
How it Works: the problem setup
• The problem must describe
correctly the desired changes
and must preserve exactly
the fixed part of the mesh.
• The prescription of the source
points and their
displacements fully defines the
RBF Morph problem.
• Each problem and its fit define
a mesh modifier or a shape
parameter.
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
How it Works: Fluent parallel morphing
• Interactive update using the GUI Multi-Sol panel and the
Morph/Undo commands.
• Interactive update using sequential morphing by the TUI command
(rbf-smorph).
• Batch update using the single morphing command (rbf-morph) in
a journal file (the RBF Morph DOE tool allows to easily set-up a run).
• Batch update using several sequential morphing commands in a
journal file.
• Link shape amplifications to Fluent custom parameters driven by
Workbench (better if using DesignXplorer).
• More options (transient, FSI, modeFRONTIER, batch RBF fit …)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
How it Works: stand alone version
• Shape modifications can be defined using the stand alone RBF
Morph GUI (CGNS plot based, accepts CGNS and stl) and/or Fluent
Add On for each shape modifications 2 files are stored (.rbf .sol).
• Volume morphing can be executed using specific morphing
commands (input: original mesh, shape modifications, shape
amplifications) or directly embedding the smoothing library
• Notice that even in the case of huge meshes just the shape
modifications files are required; with a very small demand of storage
because just the points and the coefficients of the RBF are stored.
• A shape parametric calculation grid is obtained
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Ongoing Researches about RBF
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Ongoing RBF researches
• RBF for meta modeling (DOE optimisation)
including sensitivity data (adjoint solver)
• Mapping of magnetic loads
• Interpolation of hemodynamic flow fields acquired
in vivo
• Strain and stress calculation (experimental data,
coarse FEM, isostatic lines)
• Implicit surface modeling (used for STL targets)
• FSI pressure mapping
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
RBF for the image analysis
of deformations
42.8% below 5%
17.4% in the range 5%-10%
14.9% in the range 10%-20%
13.9% in the range 20%-50%
11.0% over 50%
pts  original for
 def_pts
HPC enabling of OpenFOAM
CFD applications
28 March 2014 Cineca - BOLOGNA

pg
1
 
, pg
2
 
, pg
3
 

( deformed_RBF  deformed )  def_pts
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
RBF for the interpolation of
hemodynamics flow pattern
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
82% below 5%
5% in the range 5%-10%
8% in the range 10%-20%
4% in the range 20%-50%
1% over 50%
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
HIRENASD & RIBES
Radial basis functions at fluid Interface
Boundaries to Envelope flow results for
advanced Structural analysis
JTI-CS-2013-GRA-01-052
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
CAD controlled surfaces
• A new shape known in
advance can be inserted
using an STL target
• In the example a fillet with
radius in the range 20-30 mm
is applied to one edge of the
1000 mm side cube
• Shape blending allows a
continuous variation
• Accuracy of implicit surface is
validated against reference
analytic geometry
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
MESH2CAD - NURBS
5
Distance mesh2CAD
210
5
1.510
5
110
6
510
0
0
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
3
210
3
410
Longitudinal direction X
3
610
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Adjoint Sculpting
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Industrial Applications
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Formula 1 Front Wing
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Motorbike Windshield
(Bricomoto, MRA)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Sails Trim (Ignazio Maria Viola,
University of Newcastle)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Ship Hull (University of Leeds)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Ship Hull (University of Leeds)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Engine Air box shape
(STV FSAE Team)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Exhaust manifold
Constrained Optimization
Adjoint Solver
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Optimized vs. Original - Streamlines
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Optimization of sweep angles
(Piaggio Aero Industries)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Optimization of nacelle
(D’Appolonia)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
EU Project RBF4AERO – FP7Transport
• “Innovative Benchmark
Technology for Aircraft
Engineering Design and
Efficient Design Phase
Optimisation” – GA no.
ACP3-GA-2013-605396
• www.rbf4aero.eu
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
MIRA Reference car
(MIRA ltd)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
50:50:50 Project Volvo XC60
(Ansys, Intel, Volvo)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Generic Formula 1 Front End
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Generic Formula 1 Front End
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
What is MorphLab?
Morph lab is the convergence point of academic research, industrial
innovation, software and hardware development, where people, companies
and developers can work together to push knowledge to a higher level.
Why MorphLab?
•
•
•
partners can find fast solutions to specifical morph related industrial
cases,
hardware and software products can be tested and improved in
demanding applications,
product developers can advance their knowledge in the field of mesh
morphing sharing data and workflows.
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Aeroelastic Analysis of
Formula 1 Front Wing
Mode
Disp(mm)
Max err(mm)
Max err (%)
1
7,19
1,61
22,39
2
7,19
0,86
12,00
3
6,98
0,85
12,15
4
6,90
0,66
9,50
5
6,85
0,19
2,76
2 Ways FSI
6,98
0,00
0,00
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Aeroelastic Analysis of
Formula 1 Front Wing
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Ice accretion morphing
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
3D accretion morphing
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Carotid Bifurcation
(Orobix – CILEA)
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Hands On
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Conclusions
• A shape parametric CFD model can be defined using ANSYS Fluent
and RBF Morph – new stand alone tools allow to widen the range of
solvers (CFD, FEA) supported by RBF Morph technology.
• Parametric CFD model can be easily coupled with preferred
optimization tools to steer the solution to an optimal design that can be
imported in the preferred CAD platform (using STEP)
• Proposed approach dramatically reduces the man time required for
set-up widening the CFD calculation capability
• Local mesh control allows to enable multi-physics as well (FSI, Icing,
adjoint)
• M.E. Biancolini, Mesh morphing and smoothing by means of Radial
Basis Functions (RBF): a practical example using Fluent and RBF
Morph in Handbook of Research on Computational Science and
Engineering: Theory and Practice (http://www.cse-book.com/).
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner
Thank you for your attention!
Dr. Marco Evangelos Biancolini
E-mail: [email protected]
Web: www.rbf-morph.com
YouTube: www.youtube.com/user/RbfMorph
HPC enabling of OpenFOAM for CFD applications
28 March 2014 Cineca - BOLOGNA
www.rbf-morph.com
RBF Morph, an ANSYS Inc. Partner

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